A heavenly palace has finally returned to the Earth.
After two years of unmanned cruising in orbit, the Chinese space station Tiangong-1, or “heavenly palace” in Mandarin, has finally fallen out, crashing into the Earth’s atmosphere. At 8:16 pm Eastern time on Sunday, the school bus-size craft plummeted into the southern Pacific Ocean, the United States Joint Force Space Component Command has confirmed.
The crash ends weeks of speculation about when and where the space station might return to Earth in a fiery finale. Even in the days leading up to the crash, no one could predict the spot of the final plunge, leading to a worldwide guessing game.
UPDATE: #JFSCC confirmed #Tiangong1 reentered the atmosphere over the southern Pacific Ocean at ~5:16 p.m. (PST) April 1. For details see https://t.co/OzZXgaEX0W @US_Stratcom @usairforce @AFSpaceCC @30thSpaceWing @PeteAFB @SpaceTrackOrg pic.twitter.com/KVljDALqzi— 18 SPCS (@18SPCS) April 2, 2018
The military has not specified precisely where it fell, though NBC reports it’s somewhere between California and Hawaii.
A few pieces of Tiangong-1 may have made it through the atmosphere into the ocean. But it’s likely the majority of the space station burned up in its descent. (If you somehow find a piece of Tiangong-1, be careful. Space.com notes that what is left of the craft is likely covered with a toxic rocket fuel.)
Why no one knew where Tiangong-1 would land
Tiangong-1 launched in 2011 and was the first space station from China. It was more of a prototype than a craft meant for long-term use. It saw only two manned missions during its operational life and was retired in 2015.
But in 2016, China lost communication with and control of the station for reasons never made entirely clear. Up until that point, the plan was to bring the out-of-service station back to Earth through a controlled final descent. A few well-timed thruster blasts would have made sure the station landed safely in one of the world’s oceans.
Due to a phenomenon called orbital decay, the empty, rogue space station has been steadily cruising back toward Earth on its own.
It was hard to predict exactly when and where the space station would crash. Last week, the European Space Agency mapped a potential crash zone that covered an absolutely enormous area of the Earth. It was so hard to predict because the rate at which Tiangong-1 descended was determined in part by the friction it encountered as it collided with the very top layers of the atmosphere. The conditions there are hard to measure and hard to model in computer simulations.
That said, know the likelihood of any of us being hit by a falling piece of space debris was infinitesimally small — just one in a trillion, according to the nonprofit Aerospace Corporation. “By comparison, the risk of being hit by lightning is one in 1.4 million and the risk that someone in the US will be killed in a hurricane is about one in six million,” it explains.
There’s only one person in the history of the Space Age to be hit on the ground by debris from space: Lottie Williams. In 1997, Williams was minding her own business in a Tulsa, Oklahoma, park when a piece of disintegrated rocket hit her on the shoulder. It was just a “glancing blow,” a Wired retrospective reports, “and the debris was relatively light and probably traveling at a low velocity.”
Amazingly, the only recorded instance of a person being struck by a meteorite also occurred in the United States. (“USA! USA!”)
Ann Hodges, a resident of Sylacauga, Alabama, was hit in the stomach by a space rock when one came hurtling through the roof of her house in 1954. She got a huge, nasty bruise, and she survived.
How big of a problem is space junk?
Tiangong-1 crashed. But it’s hardly the only uncontrollable piece of metal in orbit around us.
There are more than 22,000 objects larger than 4 inches that could potentially pose a threat to our satellites or spacecraft. There’s an even greater number of tiny objects that go untracked. In all, there may be 160 million plus pieces of space garbage circling the Earth, the ESA finds. Put more simply: The space around Earth is becoming a junkyard.
And because of the speed they travel, best measured in miles per second, they’re also essentially projectiles that can blast holes in and cause damage to our satellites.
And the more space junk, the greater the threat: If these objects destroy other objects in orbit, they make even more debris. Which is concerning, considering that the amount of materials being left behind is growing.
Objects like Tiangong-1 come back down to Earth relatively quickly, within a few years. That’s because the space station is relatively close to the ground, orbiting at 120-plus miles. But objects orbiting above 620 miles can be expected to stay in space for centuries. The fear is that one day there might be so much space debris that we will have essentially made it impossible, or very dangerous, for spacecraft to leave our planet at all.